Scientists constructing tool for chemists to flag endocrine disruptors early in chemical development.

The reporter got the attribution for our project wrong (NIEHS is not financially supporting this work, but is supporting it in kind. AGC and sister organization, Environmental Health Sciences, are funded to do the project). Still though: we are glad people are interested.

A group of biologists and green chemists, supported by the extramural research division of the National Institute of Environmental Health Sciences, is developing a protocol for chemists to use to determine if the chemical they are developing is an endocrine disruptor.

Thaddeus Schug, who manages a portfolio of grants in the NIEHS Cellular, Organs and Systems Pathobiology Branch, highlighted the project during a panel discussion on practical approaches to integrating rapid testing into the chemical design process. The discussion took place Sept. 21, the second day of a workshop, “Applying 21st Century Toxicology to Green Chemical and Material Design,” which was sponsored by the National Academies’ Standing Committee on Use of Emerging Science for Environmental Health Decisions. Schug says the group has been working for the last year on developing a protocol, and the guiding principles behind it, to determine whether a chemical under development is toxic, and how and where testing should be performed.

“We focus on endocrine disruption, but our guiding principles and protocol could be developed to capture all forms of toxicity,” he said. The protocol is not regulatory, Schug said, but a guide chemists can follow – as they develop a chemical – to give them confidence as to whether the substance is or is not an endocrine disruptor.

The group, which includes non-governmental organizations, academics and green chemistry leaders, has come up with a tiered system. “What we propose to do is put the fastest, cheapest testing up front – the computational modeling, followed by high throughput screening and the zebrafish models,” Schug said. That would be followed up with more specific testing as a chemical moves further along the development process.

“The idea is if a chemist hits a positive early on, he’d either go back to the drawing board, or if that positive was in a specific area [i.e. an estrogen receptor in a high throughput assay], he’d follow that up with more comprehensive assays,” Schug said. “A hit anywhere along the tiered system” means the chemist has to pull back, reanalyze or throw the chemical out, he said.
“The idea is to do the fastest, cheapest test early on, so the chemist can weed out those problem chemicals early on in development so it’s not a costly procedure,” Schug said.

The idea of the protocol “arose from a great sense of frustration” in the endocrine disruptor community, Bruce Blumberg, a professor of developmental and cell biology at the University of California, Irvine who also is working on the project, said during the panel discussion. This frustration stemmed from “hearing things like, ‘Well, you can’t test for endocrine disruptors,’ which the American Chemistry Council says,” Blumberg noted. “We know very well how to test for endocrine disruptors, how to test for endocrine disruptor activities from in vitro all the way to animal studies,” he said. “So we said this is a gap that has to be filled, and we got together to fill that gap.”

The protocol is voluntary, Blumberg noted. “We suggest this if you want to screen for endocrine activity in your chemicals and make them more green – this is the way we think you should do it. We’re providing an alternative approach interested parties can use to make the best chemicals they can,” he said.

Richard Denison, senior scientist at Environmental Defense Fund, welcomed the protocol’s development, saying “it really flips the concept of tiered testing around.”
Usually in tiered testing, a chemical only advances to the next level of testing if it is flagged for an effect at an earlier level, “which puts a huge question mark around the extent to which false negatives are being missed.”

But in the case of the protocol, “you’re advancing things that don’t raise red flags to the next level [of testing], increasing the confidence that you didn’t miss anything,” Denison said. “I think that’s a really intriguing approach.”
(Read full article here.)
– Liz Buckley